Dial for wrist watch and a method of making the same

ABSTRACT

A dial for a wrist watch comprises a dial body formed of a flat plate of aluminum and rivet like pin members made of aluminum material and for securing supporting the dial plate body to a time-keeping mechanism. The head portion of each pin member is formed so as to fit into a recess formed on the reverse surface of the body and being integrally fixed to the recess by means of ultrasonic wave welding. Also, a method of making the dial for the wrist watch is characterized in that when the head portion of the pin member is joined to the recess, a chip of the ultrasonic wave welding machine is pressure bonded to the head portion to provide the ultrasonic wave vibration so as to integrally join the head portion to the recess.

United States Patent 191 Shimizu DIAL FOR WRIST WATCH AND A METHOD OFMAKING THE SAME [76] Inventor: Noriaki Shimizu, 521-5, Imafuku,

Ohaza, Saitamaken, Kawagoe, Japan 22 Filed: Jan. 23, 1973 21 Appl. No.:326,023

[30] Foreign Application Priority Data Feb. 1, 1972 Japan 47-1154] 52us. on ss/127 B, 58/127 R [51] Int. Cl. G04b 29/00 [58] Field of Search58/127 R, 127 B, 126 R, 58/126 A; 29/177, 470.1

[56] References Cited UNITED STATES PATENTS 1,708,293 4/1929 Fitch58/127 B 3,523,845 4/1970 Robertson 29/470.1 X

FOREIGN PATENTS OR APPLICATIONS 348,363 8/1960 Switzerland 58/127 B Apr.16, 1974 Primary Examiner-Stephen J. Tomsky Assistant Examiner-U. Weldon[5 7] ABSTRACT A dial for a wrist watch comprises a dial body formed ofa flat plate of aluminum and rivet like pin members made of aluminummaterial and for securing supporting the dial plate body to atime-keeping mechanism. The head portion of each pin member is formed soas to fit into a recess formed on the reverse surface of the body andbeing integrally fixed to the recess by means of ultrasonic wavewelding. Also, a method of making the dial for the wrist watch ischaracterized in that when the head portion of the pin member is joinedto the recess, a chip of the ultrasonic wave welding machine is pressurebonded to the head portion to provide the ultrasonic wave vibration soas to integrally join the head portion to the recess.

2 Claims,' l3 Drawing Figures PATENTEIJAPR 15 I974 13 803 8332 saw a [If2 DIAL FOR WRIST WATCII AND A METHODOF MAKING THE SAME SUMMARY OFINVENTION:

The present invention relates to a dial structure for a wristwatch andto a method of making the same, and

. 'more particularly to a dial that is provided with a pin for securingthe dial to a time-keeping mechanism and a method of joining the pin tothe dial.

According to the broad concept of the present invention, the dial forthe wrist watch comprises a dial body and a pin bonded to its reversesurface. The pin is in serted into a hole formed in the timekeepingmechanism and a set screw is urged against the pin in a right angledirection whereby the dial is fixed on the upper surface of thetimekeeping mechanism.

The conventional dial is made of brass and a hollow pin in bonded bymeans of a soldering means. Thus the pin is soldered on the dial bysoldering; for example, silver solder is sealed inside of the hollow pinand this pin is tack welded to the dial by spot welding. Thereafter thesilver solderis melted by a burner or furnace, and the joint is formedby the application of the silver solder.

However, according to this welding method, there are disadvantagesthatnot only involve the troublesome work of performing tack weldingprior to the soldering, and also a substantial high degree technique isrequired. Further, there is considerable difficulty involved even if thepin is tack welded to the dial body nickel, The pin can easily be bentdue to the high temperature heating action of the furnace or burner whenthe dial is fixed to the time-keeping mechanism, the bent pin obviouslymust be straightened. Further more, at the time of welding, the silversolder and flux flow as an integral body which leaves a convex mark onthe periphery of the welded portion, and such a convex mark posesaproblem when the dial is fixed to the timekeeping mechanism. v

Also, the brass which is the material of the conventional. dial hasdisadvantages such as it is more expensive than aluminum, its weight isheavier and also it has the difficulty of requiring forming work orsurface treating and the like. Also, when the dial making involveselectroplating with nickel, cyanide is used which is poisonous and whichtherefore is potentially harmful to the human body. Also, the residuetherefrom may eventually flow to rivers which will become a publichazard.

On the other hand, heretofore, use of aluminum as the material inconstructing the dial has been attempted. Even though the weldingtechnique of aluminum is advanced, there is a distinct disadvantage thatthe strength of the dial is reduced during such process. The presentstatus of the art is that efforts of making an aluminum dial of a highprecision as a time-keeper part by a practical method has beenunsuccessfulyAdditional disadvantages of this process are enumerated inthefollowing; (1) when the pin is joined to the dial body by means ofsoldering, a convex mark is produced on the periphery of the weldedportion as mentioned in the foregoing; (2) since the dial body is to beof a thin wall thickness and its volume is to be small, its structureand material necessarily become annealed by the heating action ofsoldering which results in a substantial remarkable loss of strength,and returning it to its original strength is difficult; (3) although theforegoing disadvantage (2) can be eliminated if aluminum solder thatmelts at low temperature is used, in such a process alumite is formedand the aluminum solder and flux are not highly resistant to chemicalsalso erosion may occur and the joint portion of the pin tends toseparate.

When aluminum is used as the material for the dial for the wrist watch,the foregoing disadvantages can be overcome. Further many advantages canbe obtained with a dial made of aluminum as compared with theconventional dial made of brass. Some examples are (1) the dial can bemade of a light weight; (2) the post or succeeding processing ortreatment such as forming, surface coating and printing and the like canbe easily performed; (3) desirable designs can be provided and (4') thedial can be constructed at low cost.

Under the circumstances as outlined above, the present inventor hasconfirmed, as a result of energetical studies, a method of making thedial for wrist watch method made of aluminum material which is freecompletely from the foregoing disadvantages.

The present invention is characterized in that the dial body is formedof aluminum material a recess is formed at a predetermined position onthe body; a rivet like pin member is formed of aluminum or similarmaterial; a head portion of the pin member fits into the recess; and thehead portion and the recess are joined by the welding energy of anultrasonic wave.

BRIEF DESCRIPTION OF DRAWINGS: I

FIGS. 5 and 10 are cross sectional views of the condition where thepin'is welded to the dial by the chip of the ultrasonic wave weldingmachine;

FIGS. 6 and 111 are bottom plan views, partially in section, of the dialbody and the pin integrally welded together;

FIG. 7 is a cross sectional view showing one adverse example where thepin is welded to the dial body by the chip of the ultrasonic wavewelding machine;

FIG. 8 is a perspective view of the second embodiment of the pin;

FIG. 12 is a cross sectional view of the chip used for welding the pinof the second embodiment to the dial plate; and

FIG. 13 is a cross sectional view of a structural arrangement whereinthe dial is welded by the conventional method to the pin and thedial-pin unit is fixed to the time-keeping mechanism.

PREFERRED EMBODIMENT OF THE INVENTION:

Referring now to the accompanying drawings, two preferred embodiments ofthe invention will be described in detail with specific reference toFIGS. 2-6 and FIGS. 8-ll2, respectively. In FIG. I, a circular flat dialplate 10 is provided with a circular center hole 11 and a rectangularaperture 12. As shown in FIG. 3 and FIG. 4, a circular recess 13 isformed in the vicinity of the periphery of the reverse surface of thedial body 10. The recess 13 is formed by measuring a predeterminedposition on the dial with the use of a jig for accurately positioningand by boring the recess with an endmill or dia. The pin 15 and the dialbody 10 are secured to a time-keeping mechanism. The pin 15 is formedwith a rivet like shape as shown inFIG. 2 is integrally provided with ahead portion 14 of a flat circular shape, and is made of aluminum orsimilar material. The diameter of the head portion l4is slightly smallerthan the diameter of the recess 13, and also its wall thickness is equalto the depth of the recess 13 or is slightly shallower than the depth.

As shown in FIG. 5, in order to weld the pin 15 to the dial body 10,after fitting the head portion 14 to the recess 13, a hollow portion 16aof the chip 16 of the ultrasonic wave welding machine is inserted tooperatively contact the pin 15. Thetip portion of the chip l6isoperatively urged against the head portion 14, by the ultrasonic waveoscillation being applied thereto When the oscillation is applied, therecess 13 and the head portion 14 are thereby welded integrally by thewelding energy of the ultrasonic wave.

Since the pin 15 that is welded to the dial body 10 is employed forsecuring the dial to the time-keeping mechanism, it is required to havea high tensile strength and bending strength.

According to end results of an experiment conducted by the presentinventor, a thickness of the head portion 14 was made 0.18 mm, itsdiameter was 0.9 mm, a diameter of the pin 15 was 0.65 mm,; the pressureof the chip 16 for the head portion 14 was kg, and its pressure contacttime was 0.25 sec., the current of the ultrasonic wave welding machinewas 2.5A, and the ultrasonic wave welding machine whose oscillatingfrequency was 19.5 KI-I was used; the pin 15 whose recess 13 was weldedto the head portion 14 could withstand the tensile strength of 6 kg andalso could withstand the bending strength (angle of 20) of 15 times inthe right and left directions or forward and backward directions, andsuch tensile strength and the bending strength having such values tosubstantially surpasses the tensile strength and bending strengthordinarily required for welding of the the pin to the dial plate body.

In the present invention, the saliant features are that, as mentioned inthe foregoing, the recess 13 being provided in the dial plate body 10,the head portion of the pin 15 being fitted and ultrasonically weldedinto the recess 13 wherebythe joint surface of both elements can be madelarger thus stronger. Also, with the foregoing arrangement, when theabove-mentioned joining is made, there are advantages in that theerection of the pin 15 on the surface of-the dial body and theapplication of the pressure of the chip 16 to the pin become extremelyeasy.

FIG. 6 illustrates the joining structure of 13 and the head portion 14.It can be recognized that a welded portion 17 is formed in ring shapeand the reason for such form is that the tip portion of the chip 16 isformed in ring shape and thusly is made to correspond to the portionthat is that to be urged against. The pressure contacting portionproduces a strong abrading action as compared with the other portion. Inorder to join not only the ring like welding portion 17 but also theother portion, it may be considered that the pressure of the chip 16against the head portion 14 can be made greater and its pressurecontacting time can be prolonged. However the pressure and the pressurecontacting time should not exceed certain maximum values. As shown inFIG. 7, there in such a situation, there is a possible adverse effect inthat a bulged portion 18 can be formed on the periphery of the headportion 14. The bulged portion 18 becomes an obstacle in the case wherethe dial plate body 10 is fixed to the timekeeping mechanism. Also theconvex mark whose shape can be similar to the head portion 14 isproduced on the surface of the dial plate body 10,or the concave portion13 is broken and the finish of the surface of the dial plate 10 becomesdeteriorated.

As shown in FIG. 8, the pin 115 is provided with an enlarged diametertapered neck portion 115a at the joint of the stem portion and the headportion 114. This enlarged neck portion does not become a problem whenthe dial body is fixed to the time-keeping mechanism. The neck portion aplays a role of preventing the shearing off the pin 115 from the stemportion of the pin 115 from the head portion 114 when the force of afixed tensile and/or bending strength is applied to the pin 115. Namely,when the pin 115 is being welded to the dial body 10 the stem portion ofthe pin 115 may be sheared off from the head portion 114 when the anexcess tensile and/or the bending force is applied to the pin 115.However, with the pin 115 being an enlarged provided with neck portion115a at its stem portion, there is a substantial increase in the tensilestrength and bending strength as compared with the ar rangement wherethe pin which is not provided the enlarged neck portion 115a.

Also, as shown in FIG. 9 and FIG. 10, the dial body 110 is provided witha different shaped surface in the recess, according to the secondembodiment. A recess 113 is provided with a surface 113a whose center ormedial section is elevated and is tapered from the me dial section tothe periphery of the recess. The projecting surface 113a producesabrading action that is necessary for its joining to the center surfaceof the head portion 114. Therefore when the required tensile and- /orbending force is applied to the pin 115, it plays a role of preventingthe shearing off of the head portion 114 from the concave portion 113.Namely, as described previously, the head portion 14 for the recess 13may be sheared off from the recess 13 when an excess tensile and/orbending force is applied to the pin as the ring like portion 17 along isbeing integrally welded thereto. Where the recess 113 is provided withthe surface 113a the necessary abrading action is produced on recess 113and the center surface of the head portion 114 when the tip portion ofthe chip 116 is pressure contacted with the head portion 114. Therefore,as shown in FIG. 11, in addition to a welded portion 117, the weldedportion 119 is formed on the center surface. As a result, the tensileand/or bending strength for the pin 115 becomes remarkably improved ascompared with a recess that has not been provided with the projectingsurface 113a.

In the present invention, the head portion 114 of the pin 115 beingprovided with an enlarged neck portion 115a can be welded to the recess113. Also, the head portion of the pin 115 can be welded to the recess113 that is provided with the surface 113a. Therefore, variousstructural arrangements of the elements can be effected.

As shown in FIG. and 12, the chip 116 has a structure which issubstantially identical with that of the chip 16, with the exceptionthat a tapered expanded portion lll6b is provided at the tip of the holewhose shape is adapted to engage with the enlarged neck portion 1115a.

In FIG. 13, the conventional dial 210 is provided with a pin 2115. Thepin 215 is made with a hollow shape, and inside thereof is sealed withsilver solder 300. The pin 215 is welded to the dial 210 by means of thesilver solder 300 the disadvantage of which has already been explained.The dial 210 having been mounted in contact with pin 215, as shown inFIG. 13, is then inserted in a time-keeping mechanism 301. A set screw302 is pressure contacted with the pin 215 at right angles from thelateral direction whereby the pin is fixed to the time-keeping mechanism301.

It is to be noted in the present invention that the dial bodies It) and110 may be made of an alloy whose prin- 1 cipal component is aluminumwhich alloy can be welded by ultrasonic welding. Also instead ofproviding the tapered surface 113a on the recess 113, a portion whoseshape is similar to the tapered surface 1130 may be provided on thecenter surface of the head portion 114. Also, the present invention isnot to be limited to the numerical values described in the foregoingdescription.

What is claimed is:

1. A dial structure for a wrist watch comprising in combination:

a dial body formed of a flat plate of aluminum and having front and rearsurfaces, said dial body having a plurality of circular recessespositioned on its rear surface adjacent the periphery thereof, each ofsaid recesses having an inner surface continuously tapering from anelevated medial section to the periphery thereof; and

a plurality of circular rivet like pin members, each of said pin membersformed of an aluminum material and having elongated stem and flat headportions, said stem portion integrally joined with said flat headportion and adapted to engage with a time keeping mechanism, said stemportion having an enlarged neck portion at the joint of said stemportion and said flat head portion, said enlarged tapered neck portionadapted to engage withan ultrasonic welding machine, said flat headportion of each of said pin members fixedly joining in a perpendicularmanner with said elevated medial section of each of said inner surfacesof said recesses, respectively, of said dial body, said joint betweensaid flat head portion and said elevated medial section adapted to beaccomplished by the welding of said ultrasonic welding machine.

2. A dial structure for a wrist watch according to claim 5, wherein saidenlarged neck portion tapers from a large cross sectional area at thejoining peripheral line to a smaller cross sectional area a shortdistance from said joining peripheral line and said smaller crosssectional area at the connecting peripheral line between said-neckportion and the body of said stem portion is substantially equal to thecross sectional area of the body of said stem portion.

l= l= =l

1. A dial structure for a wrist watch comprising in combination: a dialbody formed of a flat plate of aluminum and having front and rearsurfaces, said dial body having a plurality of circular recessespositioned on its rear surface adjacent the periphery thereof, each ofsaid recesses having an inner surface continuously tapering from anelevated medial section to the periphery thereof; and a plurality ofcircular rivet like pin members, each of said pin members formed of analuminum material and having elongated stem and flat head portions, saidstem portion integrally joined with said flat head portion and adaptedto engage with a time keeping mechanism, said stem portion having anenlarged neck portion at the joint of said stem portion and said flathead portion, said enlarged tapered neck portion adapted to engage withan ultrasonic welding machine, said flat head portion of each of saidpin members fixedly joining in a perpendicular manner with said elevatedmedial section of each of said inner surfaces of said recesses,respectively, of said dial body, said joint between said flat headportion and said elevated medial section adapted to be accomplished bythe welding of said ultrasonic welding machine.
 2. A dial structure fora wrist watch according to claim 5, wherein said enlarged neck portiontapers from a large cross sectional area at the joining peripheral lineto a smaller cross sectional area a short distance from said joiningperipheral line and said smaller cross sectional area at the connectingperipheral line between said neck portion and the body of said stemportion is substantially equal to the cross sectional area of the bodyof said stem portion.